A blow to AIT, AMT

To me one of the pieces of evidence that Indians have been speaking Indo-European languages well before the hypothetical Aryan Invasion or Aryan Migration is the lack of geographic names with non-Indo-European roots in the oldest preserved compositions that we have.  If there was an incursion of Indo-European language speakers between 1900 BC and 1500 BC, the natives that they encountered also belonged to the same language group.

But here is some genetic evidence that also weighs against any migration or invasion.

So if there is a European component in Indian genes, that event happened much earlier than the decline of the Harappan civilisation and not because of the hypothetical Aryan migration around 1500 BCE.